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SubjectRe: [PATCH v7 00/21] Move all drivers to a common dma-buf locking convention
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Am 18.10.22 um 01:07 schrieb Dmitry Osipenko:
> On 10/17/22 20:22, Dmitry Osipenko wrote:
>> Hello,
>>
>> This series moves all drivers to a dynamic dma-buf locking specification.
>> From now on all dma-buf importers are made responsible for holding
>> dma-buf's reservation lock around all operations performed over dma-bufs
>> in accordance to the locking specification. This allows us to utilize
>> reservation lock more broadly around kernel without fearing of a potential
>> deadlocks.
>>
>> This patchset passes all i915 selftests. It was also tested using VirtIO,
>> Panfrost, Lima, Tegra, udmabuf, AMDGPU and Nouveau drivers. I tested cases
>> of display+GPU, display+V4L and GPU+V4L dma-buf sharing (where appropriate),
>> which covers majority of kernel drivers since rest of the drivers share
>> same or similar code paths.
>>
>> Changelog:
>>
>> v7: - Rebased on top of recent drm-misc-next.
>>
>> - Added ack from Jason Gunthorpe to the RDMA patch.
>>
>> - Added iosys_map_clear() to dma_buf_vmap_unlocked(), making it fully
>> consistent with dma_buf_vmap().
>>
>> v6: - Added r-b from Michael Ruhl to the i915 patch.
>>
>> - Added acks from Sumit Semwal and updated commit message of the
>> "Move dma_buf_vmap() to dynamic locking specification" patch like
>> was suggested by Sumit.
>>
>> - Added "!dmabuf" check to dma_buf_vmap_unlocked() to match the locked
>> variant of the function, for consistency.
>>
>> v5: - Added acks and r-bs that were given to v4.
>>
>> - Changed i915 preparation patch like was suggested by Michael Ruhl.
>> The scope of reservation locking is smaller now.
>>
>> v4: - Added dma_buf_mmap() to the "locking convention" documentation,
>> which was missed by accident in v3.
>>
>> - Added acks from Christian König, Tomasz Figa and Hans Verkuil that
>> they gave to couple v3 patches.
>>
>> - Dropped the "_unlocked" postfix from function names that don't have
>> the locked variant, as was requested by Christian König.
>>
>> - Factored out the per-driver preparations into separate patches
>> to ease reviewing of the changes, which is now doable without the
>> global dma-buf functions renaming.
>>
>> - Factored out the dynamic locking convention enforcements into separate
>> patches which add the final dma_resv_assert_held(dmabuf->resv) to the
>> dma-buf API functions.
>>
>> v3: - Factored out dma_buf_mmap_unlocked() and attachment functions
>> into aseparate patches, like was suggested by Christian König.
>>
>> - Corrected and factored out dma-buf locking documentation into
>> a separate patch, like was suggested by Christian König.
>>
>> - Intel driver dropped the reservation locking fews days ago from
>> its BO-release code path, but we need that locking for the imported
>> GEMs because in the end that code path unmaps the imported GEM.
>> So I added back the locking needed by the imported GEMs, updating
>> the "dma-buf attachment locking specification" patch appropriately.
>>
>> - Tested Nouveau+Intel dma-buf import/export combo.
>>
>> - Tested udmabuf import to i915/Nouveau/AMDGPU.
>>
>> - Fixed few places in Etnaviv, Panfrost and Lima drivers that I missed
>> to switch to locked dma-buf vmapping in the drm/gem: Take reservation
>> lock for vmap/vunmap operations" patch. In a result invalidated the
>> Christian's r-b that he gave to v2.
>>
>> - Added locked dma-buf vmap/vunmap functions that are needed for fixing
>> vmappping of Etnaviv, Panfrost and Lima drivers mentioned above.
>> I actually had this change stashed for the drm-shmem shrinker patchset,
>> but then realized that it's already needed by the dma-buf patches.
>> Also improved my tests to better cover these code paths.
>>
>> v2: - Changed locking specification to avoid problems with a cross-driver
>> ww locking, like was suggested by Christian König. Now the attach/detach
>> callbacks are invoked without the held lock and exporter should take the
>> lock.
>>
>> - Added "locking convention" documentation that explains which dma-buf
>> functions and callbacks are locked/unlocked for importers and exporters,
>> which was requested by Christian König.
>>
>> - Added ack from Tomasz Figa to the V4L patches that he gave to v1.
>>
>> Dmitry Osipenko (21):
>> dma-buf: Add unlocked variant of vmapping functions
>> dma-buf: Add unlocked variant of attachment-mapping functions
>> drm/gem: Take reservation lock for vmap/vunmap operations
>> drm/prime: Prepare to dynamic dma-buf locking specification
>> drm/armada: Prepare to dynamic dma-buf locking specification
>> drm/i915: Prepare to dynamic dma-buf locking specification
>> drm/omapdrm: Prepare to dynamic dma-buf locking specification
>> drm/tegra: Prepare to dynamic dma-buf locking specification
>> drm/etnaviv: Prepare to dynamic dma-buf locking specification
>> RDMA/umem: Prepare to dynamic dma-buf locking specification
>> misc: fastrpc: Prepare to dynamic dma-buf locking specification
>> xen/gntdev: Prepare to dynamic dma-buf locking specification
>> media: videobuf2: Prepare to dynamic dma-buf locking specification
>> media: tegra-vde: Prepare to dynamic dma-buf locking specification
>> dma-buf: Move dma_buf_vmap() to dynamic locking specification
>> dma-buf: Move dma_buf_attach() to dynamic locking specification
>> dma-buf: Move dma_buf_map_attachment() to dynamic locking
>> specification
>> dma-buf: Move dma_buf_mmap() to dynamic locking specification
>> dma-buf: Document dynamic locking convention
>> media: videobuf2: Stop using internal dma-buf lock
>> dma-buf: Remove obsoleted internal lock
>>
>> Documentation/driver-api/dma-buf.rst | 6 +
>> drivers/dma-buf/dma-buf.c | 216 +++++++++++++++---
>> drivers/gpu/drm/armada/armada_gem.c | 8 +-
>> drivers/gpu/drm/drm_client.c | 4 +-
>> drivers/gpu/drm/drm_gem.c | 24 ++
>> drivers/gpu/drm/drm_gem_dma_helper.c | 6 +-
>> drivers/gpu/drm/drm_gem_framebuffer_helper.c | 6 +-
>> drivers/gpu/drm/drm_gem_ttm_helper.c | 9 +-
>> drivers/gpu/drm/drm_prime.c | 6 +-
>> drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c | 2 +-
>> drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 2 +-
>> drivers/gpu/drm/i915/gem/i915_gem_object.c | 14 ++
>> .../drm/i915/gem/selftests/i915_gem_dmabuf.c | 16 +-
>> drivers/gpu/drm/lima/lima_sched.c | 4 +-
>> drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 4 +-
>> drivers/gpu/drm/panfrost/panfrost_dump.c | 4 +-
>> drivers/gpu/drm/panfrost/panfrost_perfcnt.c | 6 +-
>> drivers/gpu/drm/qxl/qxl_object.c | 17 +-
>> drivers/gpu/drm/qxl/qxl_prime.c | 4 +-
>> drivers/gpu/drm/tegra/gem.c | 17 +-
>> drivers/infiniband/core/umem_dmabuf.c | 7 +-
>> .../common/videobuf2/videobuf2-dma-contig.c | 22 +-
>> .../media/common/videobuf2/videobuf2-dma-sg.c | 19 +-
>> .../common/videobuf2/videobuf2-vmalloc.c | 17 +-
>> .../platform/nvidia/tegra-vde/dmabuf-cache.c | 6 +-
>> drivers/misc/fastrpc.c | 6 +-
>> drivers/xen/gntdev-dmabuf.c | 8 +-
>> include/drm/drm_gem.h | 3 +
>> include/linux/dma-buf.h | 17 +-
>> 29 files changed, 325 insertions(+), 155 deletions(-)
>>
> Applied to drm-misc-next

Finally! Fingers crossed that all corner cases where fixed during the
review.

But if anything shows up feel free to loop me in to help fixing things.

Thanks a lot for doing this,
Christian.


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